[Bug tree-optimization/49352] [4.7 Regression] -fcompare-debug failure with -O2 -ftree-vectorize

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49352

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |irar at gcc dot gnu.org
         AssignedTo|unassigned at gcc dot       |jakub at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-06-10 10:28:28 UTC ---
The following fixes the -fcompare-debug failure:
--- gcc/tree-vect-loop.c.jj        2011-05-31 08:03:10.000000000 +0200
+++ gcc/tree-vect-loop.c        2011-06-10 12:04:28.000000000 +0200
@@ -1719,10 +1719,11 @@ vect_is_slp_reduction (loop_vec_info loo
       nuses = 0;
       FOR_EACH_IMM_USE_FAST (use_p, imm_iter, lhs)
         {
+          if (is_gimple_debug (USE_STMT (use_p)))
+            continue;
+
           use_stmt = USE_STMT (use_p);
           nuses++;
-          if (is_gimple_debug (use_stmt))
-            continue;

           /* Check if we got back to the reduction phi.  */
           if (gimple_code (use_stmt) == GIMPLE_PHI

but the code still looks questionable to me.  It is using use_stmt after the
loop, but what does use_stmt contain?  The last use, which can be outside of
the loop, rather than the single loop use.  So, if nuses > 1, which use_stmt
you actually want?